| First Author | Weyer K | Year | 2011 |
| Journal | Nephrol Dial Transplant | Volume | 26 |
| Issue | 11 | Pages | 3446-51 |
| PubMed ID | 21926402 | Mgi Jnum | J:181393 |
| Mgi Id | MGI:5311266 | Doi | 10.1093/ndt/gfr525 |
| Citation | Weyer K, et al. (2011) Mouse model of proximal tubule endocytic dysfunction. Nephrol Dial Transplant 26(11):3446-51 |
| abstractText | BACKGROUND: Several studies have indicated the central role of the megalin/cubilin multiligand endocytic receptor complex in protein reabsorption in the kidney proximal tubule. However, the poor viability of the existing megalin-deficient mice precludes further studies and comparison of homogeneous groups of mice. METHODS: Megalin- and/or cubilin-deficient mice were generated using a conditional Cre-loxP system, where the Cre gene is driven by the Wnt4 promoter. Kidney tissues from the mice were analysed for megalin and cubilin expression by quantitative reverse transcription-polymerase chain reaction, western blotting and immunohistochemistry. Renal albumin uptake was visualized by immunohistochemistry. Twenty-four-hour urine samples were collected in metabolic cages and analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and western blotting. Urinary albumin/creatinine ratios were measured by ELISA and the alkaline picrate method. RESULTS: The Meg(lox/lox);Cre(+), Cubn(lox/lox);Cre(+) and Meg(lox/lox), Cubn(lox/lox);Cre(+) mice were all viable, fertile and developed normal kidneys. Megalin and/or cubilin expression, assessed by immunohistology and western blotting, was reduced by >89%. Consistent with this observation, the mice excreted megalin and cubilin ligands such as transferrin and albumin in addition to low-molecular weight proteins. We further show that megalin/cubilin double-deficient mice excrete albumin with an average of 1.45 +/- 0.54 mg/day, suggesting a very low albumin concentration in the glomerular ultrafiltrate. CONCLUSIONS: We report here the efficient genetic ablation of megalin, cubilin or both, using a Cre transgene driven by the Wnt4 promoter. The viable megalin/cubilin double-deficient mice now allow for detailed large-scale group analysis, and we anticipate that the mice will be of great value as an animal model for proximal tubulopathies with disrupted endocytosis. |
